FILE PHOTO: Monsanto logo is displayed on a screen where the stock is traded on the floor of the New York Stock Exchange (NYSE) in New York City, U.S., May 9, 2016. REUTERS/Brendan McDermid/File Photo

The lawsuit seeks to block the Arkansas State Plant Board from prohibiting the use of dicamba herbicides, manufactured by Monsanto and BASF SE, during summer when the products are meant to be sprayed on soybeans and cotton engineered by Monsanto to resist the chemical.

Growers across the farm belt said this summer that dicamba hit areas other than where it was sprayed, damaging millions of acres of crops that could not tolerate the herbicides. Experts say dicamba is more likely to vaporize in high temperatures in a process known as volatility.

Terry Walker, director of the plant board, said on Friday he had not seen Monsanto’s lawsuit and declined to comment. Board spokeswoman Adriane Barnes also had no immediate comment on the complaint.

Arkansas previously prevented farmers from using Monsanto’s dicamba herbicide, called XtendiMax with VaporGrip, in 2017. The state allowed sales of a version made by rival BASF SE.

The U.S. Environmental Protection Agency (EPA) approved use of the herbicides on crops that had emerged from the ground only through next year and could stop sprayings beyond 2018 if farmers suffer another year of damage.